In a mobile communication environment, it is widely known to adopt a random access (RA) channel for communication between user equipment and the base station. The RA channel is a common channel which can be used by all user equipment. In using the RA channel instead of a dedicated channel, additional channel recognition processes are not necessary between the base station and user equipment since parameters, resources, etc., required to use the RA channel, are already set up by the base station.
Generally, usage of the RA channel for the communication is as follows. Through the RA channel, the first uplink signal is transferred when a user equipment initially accesses the base station. The RA channel may be used in uplink measurement for synchronization of physical layers. The RA channel is also used to transmit signals relating to a specific request from the user equipment to the base station. During a handover process, the RA channel is used to control the synchronization between a destination base station of the user equipment and the physical layers.
According to the conventional communication between the base station and the user equipment by using the RA channel, the base station broadcasts configuration information on the RA channel to the user equipment in cells of a service area covered by the base station. The configuration information includes RA codes and information on uplink RA channels available to the user equipment. The user equipment selects the uplink RA channel and transmits the RA codes to the base station in accordance with the configuration information on the RA channel set by the base station. Upon receiving the RA codes transmitted from the user equipment, the base station broadcasts a RA response corresponding to the received RA codes. In the RA response, the received RA codes and RA channel information are included. After receiving the RA response, the user equipment decides whether the RA codes and the RA channel information included in the RA response are respectively identical to the RA codes and the RA channel information having been transmitted from the user equipment itself. If the codes and the information are the same, the user equipment transmits an RA message for requesting a specific service. Upon receiving the RA message, the base station identifies the user equipment which transmitted the RA message and provides the requested service.
The user equipments can start communication with the base station with the RA channel mentioned above. However, there is the problem that locations or states of the user equipment which communicate with the base station through the RA channel cannot be reported to the base station.